megui / x264 problems with black area's in movies

[michaelhill]

Hello,

I hope this is the right sub forum, it wasnt clear for me.

I use the latest megui with x264 from http://x264.nl
I been doing a lot of rips with different resolutions and profiles from sharktooth to get to know the system.

Now i have chosen to use the HQ-Slowest profile. The movies i have done are near perfect quality but, I keep getting jumping blocks in black/dark area's. In some movies it is worse then others, but its almost everytime the same jumping blocks.

Example: I did an encode of The Matrix with a resolution of 720x288 at a bitrate of about 1200kb/s with the lancoz (Sharp) resize filter. The detail in the encode is stunning, but bad blocks in dark/black area's. I also used the HQ-Slowest profile and did not change the settings.

The rev of x264 i used was v667, but i also tried with v663

First i tought ffdshow was the problem, that the decoder cuases it, so i bought coreavc profesional. Although the movie looks better with coreavc, the blocks are still there. My player is windows media player classic.

By performing a search on this forum, i saw a topic were someone mentioned to tick no fast p skip. But in that profile it was already checked.

Does someone know what the problem is and how i can fix it? I tried myself for so long now, and thats why i opened this topic now.

Thanks for your help :thanks:

[check]

Try adding aadaptive quantization. In the custom commandline option add --aq-strength 0.3

[michaelhill]

thanks for your reply

Does it matter where in the command line i put it? Also in the config screen i cant add the code, it wont go in there never mind, i found that in help, so just the question below still stands

I will test that to see it that fixes it. What does this command actually do?

[check]

Basically it's a hack to fix issues like you have. If a block is detected as being both flat and black/blue, it will allocate more bits to it. This means the quality of those areas will rise, but as the bits are taken from elsewhere, other areas may suffer.

For that reason you should only use low strengths (I'd never use more than 0.5), and only when you need to. If you find you need more powerful filtering, it's usually a sign you need more bitrate first.

[michaelhill]

Basically it's a hack to fix issues like you have. If a block is detected as being both flat and black/blue, it will allocate more bits to it. This means the quality of those areas will rise, but as the bits are taken from elsewhere, other areas may suffer.

For that reason you should only use low strengths (I'd never use more than 0.5), and only when you need to. If you find you need more powerful filtering, it's usually a sign you need more bitrate first.

THanks for that explination thats clear for me now.

I was trying to get the matrix trilogy on 1400mb per movie each at the highest resolution. I am running the same encode now with that extra command you gave me, and if the beautifull details i have in the first encode, will suffer, then i need another solution. Either slightly lower the res, larger file or bring the ac3 bitrate down, the latter i proberly wont do, my ear are to good for that. I could encode the ac3 to HE-AAC from nero, thats sounds quite good in my ear, then ill still have the same res and size, but no blocks or filtering needed.

thanks to you i fully understand this now
cheers! :thanks:

[michaelhill]

The encode is done, and i have mixed feelings about the results.

The blocks are less, and less annoying. Although I experience the movie with less overal looks and quality. Seems also the grain/noise is less, and that gave such nice detail in the first one.

I just have to use a higher bitrate or use aac for audio.

Ill keep on trying!@
:thanks: